Note 16 - Segment Information - Segment Reporting Information by Capital Expenditures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital expenditures	$ 25,715	$ 10,160	$ 6,824
Assets	760,740	604,158
Flat Products Segment [Member]
Capital expenditures	19,985	7,325	5,105
Assets	560,116	409,116
Tubular and Pipe Products [Member]
Capital expenditures	5,242	2,833	1,719
Assets	200,016	194,787
Corporate Segment [Member]
Capital expenditures	488	2
Assets	$ 608	$ 255